fix: use globalThis.WebSocket instead of ws module

Node 22+ has WebSocket built-in on globalThis.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

plugin/index.ts

@@ -198,46 +198,41 @@ export default {
       const agentId = process.env.AGENT_ID || 'unknown';
 
       try {
-        // Connect to gateway via WebSocket and trigger an agent turn
+        // Connect to gateway via WebSocket and trigger an agent turn.
+        // Uses the same gateway RPC that sessions_spawn and cron use internally.
         const gatewayUrl = 'ws://127.0.0.1:18789';
-        const ws = await import('ws');
+        const WS = (globalThis as any).WebSocket ?? (await import('node:http')).default;
-        const WebSocket = ws.default || ws.WebSocket || ws;
 
         const result = await new Promise<{ sessionId?: string; error?: string }>((resolve, reject) => {
           const timeout = setTimeout(() => {
-            client.close();
+            try { client.close(); } catch {}
             reject(new Error('Gateway connection timeout'));
           }, 15000);
 
-          const client = new WebSocket(gatewayUrl);
+          const client = new (globalThis as any).WebSocket(gatewayUrl);
 
-          client.on('error', (err: Error) => {
+          client.onerror = (err: any) => {
             clearTimeout(timeout);
-            reject(err);
+            reject(err?.error || err);
-          });
+          };
 
-          client.on('open', () => {
+          client.onopen = () => {
-            // Send hello
             client.send(JSON.stringify({
               jsonrpc: '2.0',
               method: 'hello',
-              params: {
+              params: { clientName: 'harbor-forge-calendar', mode: 'backend' },
-                clientName: 'harbor-forge-calendar',
-                mode: 'backend',
-              },
               id: 1,
             }));
-          });
+          };
 
           let helloAcked = false;
 
-          client.on('message', (data: Buffer | string) => {
+          client.onmessage = (ev: any) => {
             try {
-              const msg = JSON.parse(data.toString());
+              const msg = JSON.parse(typeof ev.data === 'string' ? ev.data : ev.data.toString());
 
               if (!helloAcked && msg.id === 1) {
                 helloAcked = true;
-                // Send agent turn request
                 client.send(JSON.stringify({
                   jsonrpc: '2.0',
                   method: 'agent',
@@ -253,7 +248,7 @@ export default {
 
               if (msg.id === 2) {
                 clearTimeout(timeout);
-                client.close();
+                try { client.close(); } catch {}
                 if (msg.error) {
                   resolve({ error: msg.error.message || JSON.stringify(msg.error) });
                 } else {
@@ -263,7 +258,7 @@ export default {
             } catch {
               // ignore parse errors
             }
-          });
+          };
         });
 
         if (result.error) {